Food containers are well known and in common use in this country and throughout the world. Particularly food containers that would be typically used in the storage of food in a refrigerator or a freezer. Such food containers have been made of various plastics and include polyethylene bags, polypropylene containers, polyvinyl chloride reuseable cans. Some of these prior art containers have sealing means that attempt to attain an airtight seal. Often such an airtight seal, if attainable, can only be achieved after very careful pressure is applied about the perimeter of the cover and even then it cannot be certain that a continuous airtight seal is made throughout the perimeter contact between the cover and the bottom vessel.
In order to attain a proper seal between the cover and the bottom vessel it usually has been important to have a proper alignment between the cover and the bottom vessel usually at the perimeter where the sealing would take place. The simplicity of alignment as being an important factor is well understood. However in practice it is not easily attained. Thus both alignment and some form of pressure is important in order to attain a proper seal to produce reliable airtightness for the storage of food.
Following the essential requirement of a complete and reliable airtight seal is the secondary but also important requirement that the seal be easily releasable so that the contents of the bottom vessel would be readily available. Unsecuring of the seal of many prior art containers is not quick, is not easy, nor has it been satisfactory.
In addition to the requirements of an easily formed and effective airtight seal and the releasability of the seal, the commercial requirements dictate that the appearance of the product be acceptable to the public who would be users of the airtight sealed container.
An industrial model patent was obtained by the present assignee in Italy on Mar. 25, 1989, No. 51468, on an application that was filed with Serial No. 6979B/87 on Apr. 10, 1987. This Italian Industrial Model Patent discloses only the external features of the container and does not disclose the means for achieving an airtight seal, the aligning capabilities, nor the means for applying the pressure to achieve and perfect the airtight seal.